that modifies the log-law coefficient 
is a function of the roughness parameter
The roughness function that modifies the log-law coefficient is a function of the roughness parameter
| (164) |
where 
is the equivalent sand-grain roughness height. The function used is a slightly expanded version of the expression given in [19]:
| (165) |
where the exponent 
is expressed as:
| (166) |
and the default values of the coefficients are from [19]:
